R1234yf as a substitute of R134a in automotive air conditioning. Solubility measurements in two commercial PAG oils

• Solubility of R1234yf in two commercial PAG oils is measured between 258 K and 338 K.
• Solubility increases when temperature decreases.
• The systems show positive deviations from the Raoult's law.
• The measurements show a liquid phase splitting (partial immiscibility) in the high R1234yf mass fraction region for both systems.

Starting from January 1st 2011, as stated by the Directive 2006/40/EC, fluorinated greenhouse gases with a global warming potential (GWP) higher than 150 can not be used in automotive applications any more. For this reason, 1,1,1,2-tetrafluoroethane (R134a), commonly used for these applications, will be abandoned and substituted by refrigerants with lower GWP. In recent times, a new fluid, 2,3,3,3-tetrafluoroprop-1-ene (R1234yf) has been proposed as an interesting alternative, since it has a very low GWP and thermodynamic properties very similar to R134a. At the moment, only few data can be found on the thermodynamic properties of this new refrigerant and, in particular, its behaviour in solution with commonly used compressor lubricants is still to be evaluated. Here, solubility experimental data of R1234yf in a Polyalkylene Glycol (PAG) and in a specifically modified Double-Capped PAG (DC-PAG) commercial lubricants are measured with a static synthetic method at isothermal conditions, in the temperature range between 258 K and 338 K.